The 9/11 terror attacks changed Tiger Woods’ alleged nightclub mistress from a devoted, grieving fiancee to an attention-seeking monster, according to the man who was going to be her father-in-law.

Nightclub VIP hostess Rachel Uchitel — once the face of grieving survivors of 9/11 victims after her fiance was killed in the attacks — is now better known as one of three women linked to Woods’ burgeoning sex scandal.

“The last time I saw her was at the burial of my son — she’s not the person she appears to be now,” said James O’Grady, whose tragic son, Andy O’Grady, had been engaged to Uchitel when he perished on 9/11.

“She wasn’t trying to be in the papers [back then],” O’Grady said. “Maybe 9/11 had an impact on her and this is how she’s dealing with that.”

The Post published an iconic photo of Uchitel just after 9/11 clutching a “missing” poster of Andy O’Grady.

Speaking outside his home, Harrington Park, NJ, today, the elder O’Grady said he’s lost touch with Uchitel over the years — and was shocked to see her surface again as one of Woods’ alleged paramours.

The National Enquirer last week identified Uchitel as Woods’ gal pal, though she’s denied the allegation. She’s currently holed up in Los Angeles, huddling with her celebrity lawyer, Gloria Allred.

“I haven’t had any contact with her whatsoever,” the grieving dad said.

“He [Andy O’Grady] loved her. She was a different person then. I don’t really know anything about her [now]. You’re the ones who keep writing her up. You made her what she is, a media personality.”

The younger O’Grady was 32 and managing director for Sandler O’Neill when he died Sept. 11, 2001, after the second plane slammed into the South Tower.